sh.enableSharding()
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Definition
sh.enableSharding(database, primaryShard)Enables sharding on the specified database. Once you enabled sharding for a database, you can use
sh.shardCollection()to shard collections in that database. Themongoshmethodsh.enableSharding()wraps theenableShardingcommand.Important
mongosh Method
This page documents a
mongoshmethod. This is not the documentation for database commands or language-specific drivers, such as Node.js.For the database command, see the
enableShardingcommand.For MongoDB API drivers, refer to the language-specific MongoDB driver documentation.
Compatibility
This method is available in deployments hosted in the following environments:
MongoDB Atlas: The fully managed service for MongoDB deployments in the cloud
Important
This command is not supported in M0, M2, and M5 clusters. For more information, see Unsupported Commands.
MongoDB Enterprise: The subscription-based, self-managed version of MongoDB
MongoDB Community: The source-available, free-to-use, and self-managed version of MongoDB
Syntax
The sh.enableSharding() has the following form:
sh.enableSharding( <database>, <primary shard> // Optional. )
Parameter
The sh.enableSharding() method takes the following parameter:
Parameter | Type | Description |
|---|---|---|
String | The database for which you wish to enable sharding. | |
String | Optional. The primary shard for the database; the primary shard contains the unsharded collection for this database. In general, rather than explicitly specifying the primary shard, it is recommended to let the balancer select the primary shard instead. WarningTipIn general, you should not need to specify the primary shard. Allow the balancer to select the primary shard instead. |
Behavior
Write Concern
mongos uses
"majority" for the
enableSharding command and its helper
sh.enableSharding().
Primary Shard
In general, you should not need to specify the primaryShard in the command. Instead, allow the balancer to select the primary shard.
However, if you do specify the primary shard for a database and the database
is already enabled for sharding with a different primary shard, the
operation returns an error and the primary shard for the database
remains as before. To change the primary shard for a database, use the
movePrimary command instead.
Example
The following example, run from a mongos, enables
sharding for the test database:
sh.enableSharding("test")
To verify, run sh.status().